Among known optical range finding devices, there is one which is configured to: irradiate an object with irradiation light; capture reflected light reflected off the object with an image capturing device such as a CCD; and measure a distance to the object or a shape of the object on the basis of the acquired image data. If the irradiation light reflected off the object is weaker than background light, the range finding device of this kind may be unable to recognize the object correctly because the reflected light may be buried in the background light (noise).
With this taken into consideration, a proposal has been heretofore made on a range finding device in which a light transceiver unit for a long range where the reflected light is weak, and a light transceiver unit for a short range where the reflected light is sufficiently strong are capable of measuring a distance to a remote object and a distance to a near object independently by using irradiation light different in wavelength and blinking cycle (see Japanese Patent Application Publication No. 2010-107448, for example).